Re: [Xenomai] __ipipe_root_status exported GPL only but used to be not GPL only and is breaking other code

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On Wed, Dec 10, 2014 at 02:52:36PM -0500, Lennart Sorensen wrote:
> On Wed, Dec 10, 2014 at 08:44:58PM +0100, Gilles Chanteperdrix wrote:
> > And by the way, you are not "reverting a change". The I-pipe
> > starting with the version for Linux 3.2 was rewritten from scratch
> > and called "I-pipe core", did not you see the file names changing ?
> > So, what you have may simply have been a mistake. Or maybe not. 
> 
> I never realized changing ipipe to ipipe core was a huge change, and
> certainly never noticed it was a rewrite.  It seemed to work about the
> same with xenomai.
> 
> > And if you want to talk about stupid, using proprietary modules in
> > products based on Xenomai you redistribute is really stupidly
> > dangerous, both technically and legally.
> 
> Well to manage T1/E1 ports that was what existed.
> 
> I don't see a technical problem, we have the sources and are compiling
> from source.  The modules build and work fine on the kernel without ipipe,
> so clearly it isn't using any part of ipipe.

The technical problem is that the I-pipe relies on macro to
substitute local_irq_save and local_irq_restore in all the code
running in the linux kernel. So technically, any code which uses
local_irq_save and local_irq_restore uses the I-pipe, in an I-pipe
patched kernel. If any code runs which disables the irqs without
using these macros, because it is shipped pre-compiled, then you may
just have lost real-time guarantees.

-- 
					    Gilles.